The map nocturnal is the only replica in this exhibition. The original, the plaque beside it explains, is carefully contained in a lightless archive. This one is made from a midnight gossamer, impossibly fragile, preserved between two glass sheets. Handles on either side allow it to be picked up and held to the sky. Do so, and starlight cuts stark paths into the cloth. More than paths — cities, with names that flicker, brightening and softening, always just beyond comprehension. The plaque warns against interpreting the map as anything other than an art piece. But it lingers behind the eyes. Return the map to its plinth, look to the sky again, and the cities remain.